This subject is not new. It is however going to be a much bigger problem in the industry as I am getting calls every week from commercial and residential dealers who are besieged with complaints. The problem is concrete moisture issues, the failure of flooring material over the concrete and what and who is to blame.
Let me make one thing perfectly clear, and let this resonate in your mind to the point of paranoia, never, ever trust any concrete substrate you are going to install any floor covering material on. I don’t care if the concrete is 100 years old and there was something installed on it that was never a problem for all of that time. Sure as the sun in the sky, if you accept that there was never a problem before and there won’t be a problem when you put the new material down, your cavalier attitude about anything going wrong will come back and bite you in the behind. If the concrete never had anything installed on it, was fully exposed for its entire life and you think that nothing can go wrong, think again because the chances of an installation or product failure are too big a gamble to take.
I want you to be paranoid about having a problem or failure because preventing one is so easy and fixing one is not - it’s very painful and costly. You must test the concrete, not just the concrete below or on grade but every single floor. Whether it’s the basement of a home or a high rise; test, test, test. There are several ways to do this that will give you an indication as to if or how much moisture is present in the concrete. The calcium chloride test is the generally accepted test method for measuring and testing for moisture vapor emission. It is fairly easy to conduct and accurate. It is however, only a snapshot of the moment as to the moisture vapor emission in the concrete at the time the test is taken and the moisture levels can and do change. You can use a moisture meter that will give you an instantaneous reading or you can use the most accurate method, in my opinion, and that’s the relative humidity test for which you have to drill holes in the concrete and insert the test sleeves and probes. Even a down, dirty and stupid test done by putting a stack of newspapers on the floor will indicate whether there’s moisture in the concrete.
Depending on how much moisture is present you can find sealant materials to neutralize the condition. They may be as simple and easy as rolling on a coating of latex milk or more elaborate and advanced as the highly effective and best system from Koester products.
What can happen if you don’t seal the concrete and there’s a higher than 3 pound moisture vapor emission level? It depends on what type of flooring material you’re installing. If the carpet backing is vinyl there’s the potential for plasticizer hydrolysis caused by moisture and alkalinity from the concrete, carried up by the moisture vapor, reacting with the vinyl backing, which releases alcohols and causes an odor that smells similar to a new shower curtain. It will also make the acrylic pressure sensitive latex gummy. If the carpet has a unitary, woven synthetic or urethane type backing and is glued directly to the floor the alkalinity, carried up by the moisture vapor emission, an integral component of the concrete with a ph of at least 12.5, will destroy the tackifier in the adhesive. The result of the destruction of the adhesives adhesion will be buckles, bubbles, wrinkles and the carpet generally coming loose from the floor. If the carpet is in a basement, installed with a pad and tackless installation an odor can develop, the metal pins on the strip can rust and show on the face of the carpet and the wood tackstrip base can rot. If the carpet backing has jute in it, which some woven broadloom and rugs still have, there can be odor, rot and destruction of the material, not to mention mold that can grow on the jute. Lastly, any odor caused by any condition which is believed to be the fault of the carpet, flooring material or the installation immediately becomes the flooring dealers responsibility. You’ll be liable for peoples health, well being, moving furnishings, removing and disposing of the flooring material, remediating the substrate, replacing the carpet or flooring, moving the furnishings back in, testing the airspace, worker downtime, displacement, etc., etc. You don’t want to have this very expensive problem.
A big deal is being made out of moisture in concrete. It is a major issue because there are so many failures occurring but it is relatively easy to determine if you’re in jeopardy of a failure and fairly easy to prevent if you use the right sealants and materials. Just never trust the concrete. It’s easy to prevent problems caused by moisture in concrete if you know what’s facing you and how to remedy it. If you need help call me, we have answers to your questions.